1. Field of the Invention
The present invention relates to a nonmagnetic black toner used for the development of a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method or the like.
2. Discussion of the Related Art
Conventionally, carbon blacks have been used as a black colorant for a toner. However, the carbon blacks have some defects such that the volume specific resistance is low, so that triboelectric charges required for development cannot be maintained, whereby a sufficient degree of blackness cannot be obtained. In addition, there are also pointed out some problems in safety hygiene. Therefore, various metal oxides have been proposed as black colorants used in place of carbon black [Japanese Patent Laid-Open No. 2000-10344 (claim 1 and the like), Japanese Patent Laid-Open No. Hei 9-25126 (claim 1 and the like), and the like].
However, toners comprising metal oxides cause drastic wear of photoconductor, and this tendency is markedly exhibited especially in a contact development-type apparatus.
An object of the present invention is to provide a nonmagnetic black toner which comprises a metal oxide as a black colorant but can reduce wear of photoconductor.
These and other objects of the present invention will be apparent from the following description.